Method and structure for laser devices using optical blocking regions

• US 9,093,820 B1
• Filed: 01/24/2012
• Issued: 07/28/2015
• Est. Priority Date: 01/25/2011
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa Laser Diode, Inc. (Kyocera Corporation)
• Inventors: Raring, James W., Poblenz, Christiane, Lin, You-Da
• Primary Examiner(s): Zhang, Yuanda
• Application Number:
  US13/357,518
• Time in Patent Office: 1,281 Days
• Field of Search: 372/44.011, 372/45.01, 372/45.011
• US Class Current: 1/1
• CPC Class Codes: H01S 2301/173 The laser chip comprising special buffer layers, e.g. dislocation prevention or reduction
• CPC Class Codes: H01S 2301/18 Semiconductor lasers with special structural design for influencing the near- or far-field
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0206 Substrates, e.g. growth, shape, material, removal or bonding; specific crystal orientation H01S5/3202
• CPC Class Codes: H01S 5/2004 Confining in the direction perpendicular to the layer structure
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/2018 Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers
• CPC Class Codes: H01S 5/2031 characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/3063 using Mg
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/3213 asymmetric clading layers
• CPC Class Codes: H01S 5/3219 explicitly Al-free cladding layers
• CPC Class Codes: H01S 5/3403 having a strained layer structure in which the strain performs a special function, e.g. general strain effects, strain versus polarisation
• CPC Class Codes: H01S 5/3406 including strain compensation
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

An optical device includes a gallium and nitrogen containing substrate having a surface region and an optical blocking region of InAlN material overlying the surface region. A strain control region maintain quantum wells within a predetermined strain state. The strained region is preferably a confined heterostructure.

Claims

1. An optical device comprising:

a nitrogen and gallium containing substrate having a surface region, the surface region being in a non-polar or semi-polar orientation;

an n-type GaN material overlying the surface region;

an InAlN material or a low gallium content InAlGaN material where In_yAl_1-x-yGa_xN and x is less than about 30%, the InAlN material or the low gallium content InAlGaN material configured as an optical blocking region overlying the n-type GaN material, wherein the optical blocking region is substantially lattice matched with the nitrogen and gallium containing substrate;

an n-type cladding region overlying the optical blocking region;

a high indium content or thick InGaN region overlying the n-type cladding region, the optical blocking region having a lower refractive index than the n-type cladding region, and the high indium content or thick InGaN region having a higher refractive index than the n-type cladding region;

an active region overlying the high indium content or thick InGaN region; and

a p-type cladding region overlying the active region;

wherein the optical device is free from AlGaN and InAlGaN cladding regions.

2. The device of claim 1 wherein the active region comprises 3 to 7 quantum well regions;

whereupon the optical blocking region reduces leakage light of the substrate to less than about 1 percent.

3. The device of claim 1 wherein the optical blocking region is strained.

4. The device of claim 1 wherein the optical blocking region is n-type with a carrier concentration of 1E16 cm-3 to 1E20 cm-3.

5. The device of claim 1 wherein the optical blocking region has a thickness between 100 nm and 1500 nm.

6. The device of claim 1 wherein the optical blocking region is separated from the high indium content or thick InGaN region by about 200 nm to 1500 nm.

7. The device of claim 1 further comprising an electron blocking region of AlGaN material;

and whereupon the optical device emits a laser beam having a wavelength between 435 nm and 540 nm.

8. The device of claim 1 wherein the optical blocking region is not exactly lattice matched with the nitrogen and gallium containing substrate.

9. The device of claim 1 wherein the lattice match between the optical blocking region and the nitrogen and gallium containing substrate varies based upon crystal orientation.

10. An optical device comprising:

a gallium and nitrogen containing material having a surface region, the surface region being configured in a semi-polar or non-polar orientation;

an optical blocking region overlying the surface region, the optical blocking region comprising an InAlN material or a low gallium content InAlGaN material where In_yAl_1-x-yGa_xN and x is less than about 30%;

an n-type cladding region overlying the optical blocking region;

an InGaN strained region overlying the n-type cladding region, the optical blocking region having a lower refractive index than the n-type cladding region, and the InGaN strained region having a higher refractive index than the n-type cladding region;

an active region overlying the InGaN strained region; and

a p-type cladding region overlying the active region;

wherein the optical device is free from an AlGaN or InAlGaN cladding regions.

11. The device of claim 10 wherein the optical blocking region is substantially lattice matched with the gallium and nitrogen containing material.

12. The device of claim 10 wherein the optical blocking region is tensile strained.

13. The device of claim 10 wherein the optical blocking region is compressively strained.

14. The device of claim 10 wherein the optical blocking region comprising an n-type dopant.

15. The device of claim 10 wherein the optical blocking region comprising an n-type dopant having a carrier concentration of about 1E16 cm-3 to 1E19 cm-3 or 1E19 cm-3 to 1E20 cm-3.

16. The device of claim 10 wherein the optical blocking region comprising an n-type dopant, the n-type dopant comprising silicon.

17. The device of claim 10 wherein the optical blocking region has a thickness of about 30 to 2000 nm.

18. The device of claim 10 wherein the optical blocking region is configured about 10 to 500 nm below the active region.

19. The device of claim 10 wherein the optical blocking region is configured about 500 to 2000 nm below the active region.

20. The device of claim 10 wherein the optical blocking region is separated from the active region by at least n-type GaN.

21. The device of claim 10 wherein the active region is comprised of 3 to 7 quantum wells, each of the quantum wells comprising substantially InGaN;

wherein the plurality of quantum well regions range in thickness from 2 nm to 8 nm; and

further comprising at least one barrier region sandwiched between a pair of quantum well regions in the active region;

wherein each of the barrier regions is comprised of one of GaN, InGaN, AlGaN, and AlInGaN, and wherein each of the barrier regions has a thickness between 1.5 nm and 12 nm.

22. The device of claim 10 wherein the surface region is configured in a semi-polar orientation, the semi-polar orientation being one of {20-21}, {30-3-1} and {30-31} orientation.

23. An optical device comprising:

a gallium and nitrogen containing substrate comprising a surface region, the surface region being configured in a non-polar or semi-polar orientation;

an optical blocking region comprising low Ga content InAlGaN overlying the surface region where In_yAl_1-x-yGa_xN and x is less than about 30%;

an n-type cladding region overlying the optical blocking region;

an InGaN region overlying the n-type cladding region, the optical blocking region having a lower refractive index than the n-type cladding region, and the InGaN region having a higher refractive index than the n-type cladding region;

a plurality of quantum well regions overlying the InGaN region; and

whereupon the optical device is free from AlGaN or InAlGaN cladding regions.

24. The device of claim 23 wherein the optical blocking region is strained.